This invention concerns devices for separating water from diesel fuel which is a particular problem in colder climates. In those regions, often the presence of water in the fuel will cause the fuel filter to become clogged and the engine to quit running. It is, therefore, desired to have a simple straight-forward device which will accomplish the removal of water from the fuel with a minimum of maintenance. While several prior devices have been proposed, those devices have required periodic attention by the driver or maintenance department at intervals much shorter than any other maintenance would normally be performed. These shortcomings include the requirement that the water be drained out of the device manually and that the screen or other separating device be cleaned regularly. It is, therefore, an object of this device to be able to operate at long intervals without maintenance and which, when maintenance is required, such maintenance may be easily and expeditiously accomplished.